How to resize an image in 3 steps
- Load your image — drop it above or click to browse. Its original dimensions and file size are shown. Nothing is uploaded.
- Set the new size — type a width or height in pixels, cm or inches, use a quick preset, and keep aspect ratio on to avoid stretching.
- Resize and download — press Resize Image, check the result size and estimated file size, then download in JPG, PNG or WebP.
About resizing images by pixels, cm and inches
Screens think in pixels, printers think in centimetres and inches — and the bridge between them is DPI, dots per inch. A photo that must print at 10 × 15 cm needs 1181 × 1772 pixels at 300 DPI, but only 394 × 591 pixels at 100 DPI. This tool handles that maths for you: pick cm or inches, choose the DPI your printer or application asks for (300 for print, 72 or 96 for screen), and the pixel size is worked out automatically using the exact conversion of 25.4 mm to one inch.
Keeping the aspect ratio locked is the safe default for photographs: change the width and the height follows in proportion, so faces and objects never stretch. Unlock it only when a form demands an exact width and height that differ from the original proportions — for example a square profile picture from a wide photo — and expect some stretching in that case.
How it works
The image is drawn onto a canvas at the target pixel size and exported in your chosen format. JPG and WebP use the quality slider (higher quality means a larger file); PNG is lossless and ignores quality. The estimated file size shown after resizing comes from the actual exported file, not a guess.
Worked example
A 4000 × 3000 px photo resized by width to 10 cm at 300 DPI becomes 1181 px wide (10 ÷ 2.54 × 300). With aspect ratio kept, the height is 1181 × 3000 ÷ 4000 = 886 px, so the result is 1181 × 886 px — which prints back at exactly 10 × 7.5 cm at 300 DPI.
Frequently asked questions
Is this image resizer free?
Yes — completely free, with no signup, no watermark and no limit on how many images you resize.
What DPI should I choose?
Use 300 DPI for anything that will be printed, 150 DPI for a decent home print, and 72 or 96 DPI for screen-only use such as websites and online forms.
Will resizing make my photo blurry?
Shrinking an image stays sharp. Enlarging beyond the original size cannot add real detail, so very large enlargements may look soft — the tool still performs them if you ask.
What is the difference between JPG, PNG and WebP?
JPG is smallest for photos, PNG is lossless and best for graphics and transparency, and WebP often gives photo quality at a smaller size than JPG in modern browsers.
Is my image uploaded anywhere?
No. Resizing happens 100% in your browser using the Canvas API. Your image never leaves your device.
How do I resize to a passport size?
Use the 413 × 531 preset (35 × 45 mm at 300 DPI), or enter 3.5 × 4.5 cm with 300 DPI. For guided face framing, use our free Passport Size Photo Maker instead.
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